Slip setting mechanism for well casing



Oct. l, 1968 A. ARUTUNOFF 3,403,731

SLIP SETTING MECHANISM FOR WELL CASING Filed April 24, 1967 2 Sheets-Sheet z /fv vf/v Tof?v ARMA/5 AHUTU/VOFF By/fMf-M-f/ A TTOR/VE Y United States Patent O 3,403,731 SLIP SETTING MECHANISM FOR WELL CASING Armais Arutunoff, Bartlesville, Okla., assignor to Reda Pump Company, Bartlesville, Okla., a corporation of Delaware Filed Apr. 24, 1967, Ser. No. 633,037 7 Claims. (Cl. 166-211) ABSTRACT OF THE DISCLOSURE Slip setting mechanism for a pump in a well casing, including a body connected to the pump `and having -a depending, tubular extension. Slips are mounted on the -body and connected to a collar which is vertically slidable on the extension. The collar supports a pair of depending pivoted arms, whose lower ends carry casing engaging rollers. The arms lare Ibiased to urge -respective rollers into engagement with opposite sides of the casing, and each roller has centrifugally actuated braking means responsive to an increased speed of descent in the casing to convert rolling friction of the rollers into sliding friction which causes elevation of the collar and sets the slips.

Related application The 4present invention was primarily designed for use as an `auxiliary slip setting unit for a wire-line suspended pump installation in a well casing, such as described in my copending application Ser. No. 621,924, filed Mar. 9, 1967. The purpose of this invention is to serve as a precaution against an excessive rate of descent of the installation in the casing, which might result in injury to the pump and other elements of the installation.

However, it is to lbe understood that the invention may rbe put to other generally related uses, where it is desirable to provide ibraking means which become operable upon an excessive rate of descent in a casing.

Summary of invention Briey, the slip setting mechanism of this invention is attached to the bottom of an installation which is to 'be lowered into a well casing. The unit includes at least two arms which are Ipivotally mounted on a vertically slidable support connected to a series of slip members, the free ends of respective arms carrying rollers for engagement wit-h opposite sides of the inner periphery of the casing. The arms are normally urged outwardly to bring the rollers into rolling frictional engagement with the inner wall of the casing, under the influence of spring means. Each roller is provided with radially projectible, weighted braking means, operable by centrifugal force so that when the assembly descends at an excessive rate of speed, the centrifugal force of the rollers causes the projectible `braking means to protrude beyond the peripheries of the rollers and engage stop means which prevent further rotation of the rollers. Thus, the rolling frictional engagement of the rollers with the casing is converted into sliding frictional engagement to act as `a brake, causing the slidable support to move upwardly, to thereby set the slip members against the casing and prevent further descent of the installation.

The drawings Referring to the drawings in which numerals of like character designate similiar parts throughout the several views:

FIG. 1 is a vertical sectional view of the slip setting mechanism of the invention installed in a well casing;

FIG. 2 is a similar view taken at right angles to that shown in FIG. 1;

3,403,731 Patented Oct. 1, 1968 ICC FIG. 3 is an enlarged sectional view taken on line 3--3 of FIG. 2;

FIG. 4 is a fragmentary sectional view taken on line 4-4 of FIG. 2;

FIG. 5 is a view partially in section, showing one of the rollers 1n normal rolling engagement with the casing; and

FIG. 6- is a similar view illustrating the operation of the centrifugally actuated braking means in the rollers.

Detailed description Referring first to FIGS. 1 -and 2, 10 represents a conventional well casing into which a motor and pump installation, such as described in my said copending application, is lowered. In the illustrated embodiment, the lowermost element of the pumping assembly comprises the motor unit, the housing of which is shown at 11. A generally cylindrical slip supporting body 12 is secured by any suitable means, such as complementary threads, to the. bottom of the motor housing 11 and depends thereform lnto the casing in spaced relation to the inner periphery thereof. A tubular extension 13 is coaxially connected to the body 12 and extends downwardly therefrom into the casing.

A series of segmental, wedge-shaped slips 14 are slidably supported on the periphery of the body 12 by means of inclined grooves 15, which, as best seen in FIG. 4, comprise male dovetail portions 16, and the inclined surfaces of the slips are provided with female dovetail portions 17 so that the slips are slidably retained relative to the body 12 in a manner such that when the slips are moved upwardly, as will later appear, the body 12 expands the slips radially into engagement with the inner periphery of the casing 10. The outer surfaces of the slips 14 are provided with outwardly and downwardly directed teeth 14a to facilitate biting engagement with the casing. It may be noted that in FIG. l, only one slip is illustrated, the others having been deleated for purposes of clarity.

The tubular extension 13 slidably supports a collar 18, provided with a series of radially projecting, peripheral lugs 19 which pivotally support connecting links 20, the opposite ends of which are pivotally connected to lugs 21, depending from the bottoms of respective slips 14. Thus, the pivotal connections of the links 20 to the lugs 19 of the collar 18 and the lugs 21 of the slips, provide a double pivot arrangement which facilitates both vertical and lateral movement of the slips, as will later appear.

Diametrically opposite pivot pins 22 projecting radially from the periphery of the collar 18, respectively support depending arms 23, and the lower extremity of each arm is directed inwardly as at 24 and provided with a downwardly projecting yoke 25 for supporting the spindle 26 of a friction roller 27. The roller 27 may be formed of any suitable friction inducing material.

The inwardly directed lower ends of the respective arms 23 lie along opposite sides of the extension 13 and are urged outwardly in radially opposite directions by horizontally disposed coil spring 28 which is interposed between upright retaining abutments 29, fixed to the bent ends 24 of the arms, as best seen in FIG. 2. Thus, the rollers 27 are normally maintained in rolling frictional engagement with the inner periphery of the casing during descent of the installation therein. Preferably, the lower end of the tubular extension 13 is cut out as at 13a to accommodate the rollers 27.

The centrifugally actuated braking mechanism for the rollers 27 is best illustrated in FIGS. 5 and 6. Referring first to FIG. 5, each roller is provided with a radially, inwardly recessed well 30, opening at the periphery of the roller. Within the base of each well 30, a stud 31 having an enlarged head 31a is coaxially threaded as at 32 and serves as a guide rod for a radially projectible and retractible, weighted brake element 33. This brake element prefearbly comprises a cup-like member which is normally retained within the contines of the well by a coil spring 34 which is interposed between the enlarged head 31a of the stud 31 and the bottom of the cup-like brake element 33. For coacting with each of the brake elements 33, the inwardly directed lower ends 24 of the respective arms 23 are provided with downwardly projecting stops or abutments 35 which overlie the peripheries of the rollers 27 in sufticiently spaced relation to normally permit rotation of the rollers without obstruction. However, when the brake elements 33 are projected radially by centrifugal force, they are in line for contact with the abutments 35, as shown in FIG. 6.

In operation, when an installation carrying the slip setting mechanism at its lower end is lowered into a well casing, a normal speed of descent simply causes a rolling frictional engagement between the rollers 27 and the inner periphery of the casing. As previously pointed out, the spring 28 is of a strength to maintain this rolling frictional engagement, and serves to guide the descent of the installation. However, if, for some reason, the rate of descent of the installation is increased beyond the safety limit, the speed of rotation of the rollers 27 causes the braking elements 33 to be projected radially by centrifugal force, and upon projection beyond the peripheries of the rollers, the braking elements engage the depending abutments 35 which prevents further rotation of the rollers. Thus, the rolling frictional engagement of the rollers is converted to sliding frictional engagement which, under the influence of the pressure of spring 28, causes the elevation of the collar 18 on the tubular extension 13. The elevation of the collar 18 acts through the links 20 to force the segmental slips 14 upwardly into wedging engagement between the body 12 and the inner periphery of the casing 10, which stops the continued descent of the installation in the casing. As previously explained, the double pivotal connection of the links permits the slips to move both vertically and radially in the course of this wedging action so that no binding results.

From the foregoing, it is believed that the invention may be readily understood by those skilled in the art without further description, it being borne in mind that numerous changes may be made in the details disclosed without departing from the spirit of the invention as set forth in the following claims.

claim:

,1. A slip setting mechanism for use in lowering a pump installation in a well casing, comprising a slip supporting body xed to and depending from said installation, a series of tapered slips slidably mounted on the periphery of said body, a vertically shiftable slip actuating member supported by said body, means operatively connecting said slips to said member, at least two rollers carried by said member, rotatably engageable with opposite sides of the inner periphery of said casing upon descent therein, and roller braking means operable by a predetermined centrifugal force developed by said rollers upon an excessive speed of descent in said casing, for stopping rotation of said rollers and converting the rolling frictional engagement thereof with said casing to sliding frictional engagement, whereby said actuating member is shifted vertically to set said slips into gripping engagement with said casing.

2. A slip setting mechanism for use in lowering a pump installation in a well casing7 comprising a slip supporting body fixed to and depending from said installation, a series of tapered slips slidably mounted on the periphery of said body, a depending extension connected tovsaid body, a collar vertically slidable on said extension, means connecting said slips to said collar, at least two depending arms pivoted at one end to said collar, the opposite ends of said arms carrying rollers for engagement with the inner wall of said casing, spring means urgingthe lower ends of said arms outwardly in opposite directions to cause rolling frictional engagement of said rollers with the casing under conditions of normal speed of descent, and. centrifugally actuated braking means on respective rollers, responsive to an increased speed of descent to convert the rolling frictional engagement of said rollers and casing to sliding frictional engagement, whereby said collar is elevated on said extension to set said slips into gripping engagement with said casing.

3. Mechanism as claimed in claim 2, wherein said slips are secured to said collar by links which are pivotally connected at one end to said collar and at their other ends to respective slips, to thereby accommodate both vertical and radial movement of the slips in the course of setting.

4. Mechanism as claimed in claim 2, wherein said breaking means includes a recess on the periphery of each of said rollers to provide a radial well, a weighted brake member radially slidable in said well, spring means normally retaining said brake member within the connes of said well, and abutments on respective arms spaced from the peripheries of said rollers, whereby, upon an increased rate of descent and a resultant increased speed of rotation of said rollers, said brake members are radially projected by centrifugal force for engagement with respective abutments to convert rolling friction of said rollers to sliding friction.

5. Mechanism as claimed in claim 4, wherein each of said arms is provided with a yoke at its lower end, said rollers being rotatably mounted on spindles supported in respective yokes.

`6. Mechanism as claimed in claim 5, wherein said abutments are formed on respective yokes.

7. Mechanism as claimed in claim 5, wherein said spring means comprise a horizontal coil spring interposed between the yokes of opposite roller supporting arms.

References Cited UNITED STATES PATENTS 1,690,721 ll/ 1928 Dillon 166-209 X 1,705,192 3/1929 Leonard 166--209 2,135,253 l1/l938- Guiberson 166-211 2,214,196 9/1940 Hall 166-211 DAVID H. BROWN, Primary Examiner'. 

